Process of extraction



T. J. FAIRLEY.

PROCESS OF EXTRACTION. APPLICATION FILED JULY I4, I9I7- Patented Sept. 14, 1920.

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UNITED srArss- PATENT OFFICE.

TALIAFERRO 3'. FAIRLEY, OF NEW ORLEANS, LOUISIANA, ASSIGNOR TO SOUTHERN PINE PRODUCTS 00., INC., A CORPORATION OF LOUISIANA.

rnocnss or EXTRACTION.-

' LEY, a citizen of the United States, residing at New Orleans, in the State of Louisiana,

have invented certain new and useful Im-' provernents in Processes of Extraction, of which thefollowing is a specification, reference, being had therein-to the accompanying drawing. I

Thls invention comprlsesa process of ex-' traction. While it is capable of general application, it has been found especially useful in the recovery of turpentine, pine-oil and rosin from woodsbearing these products. I

Considerable difficulty has heretofore been encountered in the extraction of these elements. In destructive distillation, there is no rosin recovered, as it decomposes and forms tar. The pine-oil and turpentine resultants in this process have a very ofl'ensive. odor, and unless chemicals are added during distillation, they are generally discolored. In addition to this, their market value is low.

In the steam distillation, while a good grade of turpentine andpine-oil may be produced, it is necessary to add a solvent after these have been driven off, in order to recover the rosin. This solvent, in addition to being expensive, must be re-distilled in order to recover it, and these steps together with the initial cost of the solvent, render the process slow and expensive. The loss of solvent incurred is such that it renders the recovery of rosin impractical under normal market conditions. I

It is contemplated by the present invention to produce a process of extraction which will avoid the difficulties and disadvantages above enumerated; which will produce a resulting product of high grade commercially; and which will effect these results in a much more expedite manner, thus cutting down the labor cost which has heretofore been a large item in the production of these commodifies; Other objects and advantages will in part be apparent, and in part be brought out more fully in the description which follows. A drawing diagrammatically setting forth an embodiment of the process is hereto appended as a part hereof, the disclosure there- Specification of Letters Patent. -Pa,tnted Application filed July 14, 1917-. Serial No. 18 0,506.

in having been found to produce-the objects set orth, in a'satisfactory manner.

In these drawings, 1 represents a hopper for wood in the form of chips, preferably, and which may be fed into an extractor 2,

through'valve 3. A screen 4, here shown of the double mesh variety extends across the upper portion of the extractor, an opening therein being provided in alinement with the feed opening for the chips. This opening is also provided witha screen collar 5, and a slide 6, operable by a handle 7 on a rod passing through a stufling box in the side of the extractor, may be moved across the opening in the screen after the chips are inserted.

In the lower part of the digester there is provided a heating means 8, which may be of any suitable type, but a coil, perforated for the admission of steam under pressure has been found satisfactory.

A circulating system for a solvent is provided in connection with the extractor, and

Sept. 14, 1920.-

to this end pipes 9 and 10, provided with valves 11 and 12, connect the extractor with a reservoir 13. A pump 14 is also included in this system. v

In the upper portion of the extractor, and preferably in such a manner that there will be no air space when it is filled with solvent, a pipe or the like 15, having a valve 16, connects the extractor with a separator 17 The separator is provided with a heating means 18, here shown in-the form of a coil provided with a control valve 19, and having at its lower portion an outlet 20 controlled by a valve 21. ,The lower portion of the separator is also in communication with the reservoir 13, as through pipe 212K, I

which may be controlled by valve 23.

water glass 24 renders visible the height ofif livered to a suitable receptacle 31.

a For the purpose of emptyin-g'the extractor, there is provided a valve 32 and outlet 33, secured to the lower portion of the extractor.

' I have found that turpentine, and pine oil are natural solvents for rosin, but when than' water, precipitates and attaches itself to the wood or portions of the apparatus.

.the steam, up..to about 300 degr they are separated from the rosin in the course of extraction,the latter, being heavier I have also found that'if these solvents are quickly driven off the rosin remains in the wood and to regain it, a separate process using solvents, is necessary. .To prevent the precipitation of the rosin and the use of additional solvents ,or an additional step inthe extraction process, I extract the turpen tine, pine-oil and rosin all at the same time,

and in a manner which will now be described-.

.14: and pipe 9 until it has completely filled the extractor and reached the level of the dotted line in the separator. 17.

Valve 16, is now closed, the pump 14 shut down, and valve 11 closed. This leaves the extractor completely filled with water and no space therein for the volatilization of the turpentine or pine-oil. Valve 8' is now opened and live steam at boiler pressure is.

admitted to the extractor through perforated coil 8. The result is an increase in pressurewithin the retort which is allowed to rise to from about 50 to pounds to the square inch, depending upon conditions. This increase in pressure is accompanied by a corresponding increase in temperature ranging from 180 degrees F. the temperature of the water before the admission of ees F., the temperature between these points varying according to the variations in the pressure.

While the, steam is being admitted to the extractor, apressure is generated in the separator by means of the heating coil 18, the desideratum being to' maintain about equal pressures in these two vessels during the step just described. For determining the respective pressures, both the extractor and separator may be provided with. pressure gages 34, and these may be. utilized to de,- termine the temperature also of'the respective vessels.

In addition to the function of raising pressure and temperature of the contents of the retort, the admission of steam through coil 8 causes'a violent ebullition of the chips, which keeps them circulating upwardly toward the center of the retor't and ,downwardly along the sides thereof, the perforations in the coilbeing arranged to eflfect this movement. This circulation prevents packing of the chips and causes an intimate association and penetration of the water,

which in turn carries the heat into the innermost recesses of the'wood, being aided therein by the excessive pressure within the retort; f

To facilitate the exit of the water which has been driven into the wood to take the place ofthe products of extraction which,

at this stage of the process, has'considerably advanced, pressure is-let down within the extractor from time toltime. This may be effected by cutting'ofl the steam by manipulating valve 8', or by operating valve 16 to open communication with the separator when the pressure in the latter is below that in the extractor. In opening valve16, it is desirable to have nearly equal pressures, however, asit is desirable to float over, from the extractor, to

the separator, the products of extraction, as distinguished from processes in which they are blown over, or otherwise violently handled in such a way that separation of the turpentine and pine-oil might be effected, and consequent precipitation of the rosin to become attachedqto the wood chips or parts of the apparatus.

Inthe present process floating over of the v products of extraction is efiected without permitting any air space in which the more volatile constituents might become separated from the rosin, andit may also be done continuously, after the process has ioo When the pressure gages show the pres- I mitting any room at the top thereof for volatilization. 7

After the products have been floated over, .valve 16 may be closed, heat applied in the separator to efiect a separation of the tur pentine and pine-oil from the rosin, the latter collecting in the bottom of the separator where it may be "drawn'ofi by means of outlet 20 and valve 21. The pine-oil and turpentine pass over as volatile products through dome 25 to condenser 28 whence they are conducted to receptacle 31. I -While this separation is being effected, the wood chips which have been subject to extractionrmay be withdrawn from the ex-- tractor through valve 32 and outlet 33, and a new charge placed in the extractor, while whatever water remains therein may be transferred through pipe 10 to well 13.

By cracking valve 26, leaving valve 16 a slightly open and maintaining a circulation of water through the extractor by pump 14 and pipe 9, the process may be continuously effected, after heat and pressure sufficient for the process has been established in the extractor. It will be seen that these valves may be regulated 'to permit floating over of the products from the extractor to the sepa creases the amount of this product without.

the use of any additional solvent. The maintaining of approximately equal pressures in the extractor and separator permlts'.

the floating over of the rosin in combination with its solvents, as there is no room in the extractor for volatili zation, and consequently the rosin is not precipitated.

Another advantage of this process is the elimination of discoloration due to the formation of carbon. When trees have been charred, and the chips are acted on by a solvent such as gasolene, the carbon is dis solved, and permeates the rosin. .It is then a diflicult matter to reclaim it, and requires considerable time and extra steps in the process. By .the present method this carbon is not dissolved, but is merelyscreened out in the circulation system, and vin no way does it associate itself with the products of extraction.

In the continual operation of the apparatus, valve 23 may be regulated so thatthe water in the separator will be maintained at approximately the level indicated by the dotted lines, the operation of this valve perv mitting any excess of water to flow back into well 13. The water in this well is maintained heated approximately at a temperature not below 180 degrees -F., and the well itself is,- in practice of suflicient size It will be understood that I do not wish to be limited to the precise steps of this disclosure, as many changes .in the general operation are contemplated as within the scope of the invention withoutsacrificing its chief advantages.

What I-claim is 1. A process of extraction which consists in placing the material to be extracted in a closed vessel filled with water. at approximately 180 degrees F .-so as to leaveno space in the vessel unfilled, and forcing live steam into the vessel to cause an increase of pres sure therein from approximately to 70 pounds to the square inch.

.to hold enough hot water for the entire system.

2. A process of extraction which consists in acting upon materials to be extracted in an extractor completely filled with a liquid,

maintaining a pressure above atmospheric pressure in the extractor, floating over the products of extraction from the extractor to a separator by adding liquidvso as to leave no space in the extractor unfilled, and maintainingaj pressure in the separator approximately equal to that in. the extractor.

3. A process of extraction which consists in treating materials in a closed extractor completely filled with a liquid, floating over products of extraction from the extractorto a separator without reducing the quan- 4 tity of liquid in the extractor, .and maintaining an approximately equal pressure, above atmospheric, in the extractor and separator during extraction. v

In testimony whereof I affix my signature in the presence of two subscribing witnesses.

TALIAFERRO' J. FAIRLEY. Witnesses:

JAMES ATKINS,

MARY E. SMOOT. 

